Will Forte Teaches Chris the 'Flex' to Sex Up His Marriage on 'Up All Night' (VIDEO)

This week's 'Up All Night' (Wed., 8PM ET on NBC) explored a truth that new parents generally discover quite abruptly one day. They've stopped caring about how they look around the house ... and sometimes in public, too.

This tends to be more difficult for the men to handle, which is why Chris wound up reaching out to a fellow new father, played by Will Forte, for advice. Reed (Forte) agrees to come over to teach Chris a few tricks to get Reagan to make more of an effort.

The idea is for Chris to sex up his image a bit, which Reed showed him has a lot to do with your clothing, and especially your underwear. While showing off his "sexy" briefs, he let Chris in on the power of the glute flex, which lifts and adds volume to your rear-end.

Unfortunately, while Chris takes the suggestion to heart, he botches the subtlety part of the lesson and puts Reagan on the offensive. By offensive we mean she took his suggestion to a ridiculous degree, prompting us to wonder where she unearthed that posh costume. It was certainly a funnier solution than what most couples would do, which is to just fight.

And we caught that little shout-out to Kelly Bundy's hairstyle in the old video she and Ava watched. Nice one!